Olympic discus thrower Allison Randall has became the third athlete to confirm a positive drugs test from the Jamaican trials in June following the weekend's revelations by sprinters Asafa Powell and Sherone Simpson.

Randall, who competed at last year's London Games but failed to make the final, acknowledged receipt of the Jamaica Anti-doping Commission's notification of her adverse finding for a banned diuretic but, like Powell and Simpson, denied knowingly taking a performance-enhancing substance.

Powell and Simpson confirmed that they tested positive for the stimulant Oxilofrine (methylsynephrine) while two more Jamaican athletes are reported to have failed tests at the same championships.

Italian media reported on Monday that police had raided a hotel in the north of the country where sprinters had stayed and that several products had been seized.

Police said that the rooms of Canadian trainer Chris Xuereb had also been searched but that nobody had been arrested.

American former double world champion Tyson Gay also announced at the weekend that he had tested positive for a yet-to-be-revealed substance.

Gay, who has run the year's three fastest 100 metres times, had been expected to challenge Jamaican Olympic champion Usain Bolt at next month's world championships in Moscow.